Process of die forging



Aug. 12, 1924. 1,504,7 4

' E. E. JOHNSON PROCESS OF DIE YFORGING Original Filed Feb; 13 1920 2 Sheets-Sheet l I N YEN TO FF:

' ZDWA D E JbH/vso/v. B WWM/MW A 7- TORNEYS.

Aug. 12, 1924. 1,504,764

.- E. E. JOHNSON 'PROCESS OF DIE} FORGING Original Filed Feb. 13 1920 2 Sheets-Sheet 2 .Z7v vs/v TOR. E WARD E. JBH/vso/v BY A'TTOR/VEYs.

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Patented Aug. 12, 1924.

EDWARD E. JOHNSON, OF ST. PAUL, MINNESOTA.

PROCESS OF DIE FORGING.

Original application filed February 18, 1920, Serial No. 858,449. Divided and this application filed February '27, 1922.

forging cylindrical blanks after they have been heated to a temperature suitable for performing such operation. This application is a division of my prior appllcation Serial Number 358,449 filed February 13, 1920. The full objects and advantages of my invention will be apparent from the foregoing description, and the novel features embodied in my inventive idea will be particularly pointed out in the claims.

Referring to the accompanying drawings which illustrate steps in the performance of my process, Fig. 1 is a view in rspective of a section of cylindrical meta tube constituting a blank from which a coupling is made. Fi 2 to 8 are detail views show-v ing the difl'erent positions of the forging dies and coupling blank during the forging operation. Fig. 9 is a side elevational'view o the coupling after it has been finished in the dies. Fig. 10 is a viewjn perspective of me of the diemembers which 1 emlploy.

n carrying out my invention, tubular sections such as the section 12 shown in Fig. 1 are cut from a metal tubing of the proper size. The blanks thus produced are heated to the proper temperature for forging and are placed one at a time between a lurality of radially operating dies 14 which are reciprocal-ted in unison in any suitable manner such as by the mechanism disclosed in my prior application above referred to. Each die face as shown in Fig. 10 consists of a middle portion 16 and two end portions 18' which are raised above the middle portion and are inclined slightlyin upward directions as they extend away from the middle portion. These end portions are beveled at each side as indicated at 20 and at their outer ends are provided with curved depressions 22. The manner in. which the Serial No. 539,433.

blank is forged will be understood by referringto Figs. 2 to S. Fig. 2 is an end view in which the blank 12 and the dies 14 are shown in the ition which they occupy at the inception of the forging operation. The end portions of the dies are in contact with the surface of the blank, in the position here shown while as indicated by dotted lines :the middle portions of the dies have not yet reached the blank. Figs. 3 and 4 are sectional views transvers'el through the middle portion of the blank and the dies, Fi 3 showing the dies'advanced so that t ey'just contact with the blank, and Fig. 4' showingthe blank and dies in final position. In the latter figure,

the hexagonal shape of the middle portion of the coupling havingface's24 is shown. The sha e is referred to as hexagonal since the numr of (lies which I employ is preferably six. Figs. 5 and 6 are sectional views transversel through the dies and the blank midway 0; an end portion. of the latter. Fig. 5 shows the dies advanced suficiently to partly shape the blank, while Fig.- 6 shows the dies advanced into final position whereby the end portions of the coupling have areduced hexagonal exterior surface, the faces of which; are separated by longitudinal "radially extending ribs 26 which are produced onaccount of the die faces bein beveled as shown at 20 in'Fig. 10. Figs. and 8 are end views, Fig. 7 showing the dies advanced sufliciently to partly shape the blank while Fig. 8 shows the dies advanced into final position. The end of the coupling in Fig. 8 is shown with the curved portions 28 which are formed by the depressions 22 at the ends of the die faces. It will be apparent from Figs. 2 to 8 that the coupling is produced with reduced end portions or necks having cylindrical ends merging into an outer surface of hexagonal form, the faces of which are separated by reinforcing ribs which extend longitudinally from the middle portion to the extreme ends of the coupling. Fig. 9 shows the exterior appearance of the coupling after it has been shaped in the dies. By referring to Fig. 10 which shows one of the several cooperating dies, it will be a parenthow the final shape is given to t e coupling by means of the die faces. The middle portion 16 of each die face forms one of the faces 300:? the middle portion of the coupling, the end portions 18 form portions of the readily rovided with interior screw threads. y employing my process in which heated cylindrical tubular blanks are subjected to radially directed inward ressure applied at regular intervals aroun the blank to give a polygonal shape thereto, I am able to dis so with a mandrel and still maintain the interior cylindrical surface of the blank. .Since the pressure is equally distributed around the blank, there is no distortion of the internal surface from an approximately 0 lindrical shape. The result of the applied pressure is to cause an exteriorflow of metal'to roduce the polygo nal exterior shape but the interior curve of the blank acts in the manner of an arched structure and the interior cylindrical sha e 1s maintained. In the manufacture of t e coupling, the making of the end portions of polygonal shape permits the retention of the mner cylindrical surface without any interior supporting mandrel when the end portions are reduced by radial inward pressure in the dies. It is of importance that the inner surface be kept substantially cylindrical in order to provide a suitable surface for-screw-threadlng. If an attempt is made to reduce the end portions without the use of an interior mandrel and between dies,

which are concaved instead of flat, the interiorsurface will be bulged into a shape which is approximately polygonal, and

hence, not suitable for screw-threadlng.

The provision of the ribs 26 strengthens the coup ing, and theseribs serve to take up the surplus material when .the end portions are to radi contracted between the dies. The protuberouter ends of the faces of the end portions. 2

I claim:

1. The process of die-forgin which consists in heating cylindrical tu ular blanks and subjecting the end portions of said blanks to radially-directed inward pressure a plied at regular intervals around the blimk to contract .said end portions and give a polygonal exterior shape thereto.

2,. e process of die-forgin which consists in heating 0 lindrical tu ular blanks, subjeotin the en portions of said blanks y-directed inward pressure applied at regular intervals around the blank to contract said end portions and give a polygonal exterior shape thereto, and subjectin the middle portion of said blanket) rafiially-directed inward pressure applied at regular intervals around the blank to ive a polygonal exterior shape to said midfile portion.

3. The process of forming couphn whlc-h consists in cutting sections from cy indrical tubing to form anks, heati sa d blanks, subject' the end portions 0 said blanks to radia y-directed inward ressure applied at regular intervals around t e blank to contract said end portions and give a polygonal exterior shape thereto, sub ecting the middle portion of said blanks to radially-d1- rected inward ressure applied at lar intervals around the blank to give apo ygonal exterior shape to said middle port on, and providing said contracted end portions with internal screw threads.

In testimony whereof I hereunto aflix my signature.

EDWARD E. JOHNSON. 

